﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  201" 
  

  

  Genus 
  trematooPira 
  Hall 
  

   [Ety. 
  : 
  r^j^//a, 
  foramen; 
  <77r£r/)a, 
  spire] 
  

   (1859. 
  A^. 
  Y. 
  state 
  mus. 
  nat. 
  hist. 
  12th 
  an. 
  reft, 
  p. 
  27; 
  1893. 
  Pal. 
  

   N. 
  Y. 
  V. 
  8, 
  pt 
  2, 
  p. 
  124) 
  

  

  Shells 
  transverse, 
  with 
  subequally 
  convex 
  valves; 
  surface 
  radially 
  

   plicate; 
  hinge 
  line 
  straight, 
  cardinal 
  extremities 
  abruptly 
  rounded; 
  

   anterior 
  margin 
  sinuate. 
  Pedicle 
  valve 
  with 
  a 
  median 
  sinus 
  and 
  an 
  

   incurved 
  beak, 
  truncated 
  by 
  a 
  circular 
  foramen. 
  Delthyrium 
  cov- 
  

   ered 
  by 
  two 
  short 
  incurved 
  plates, 
  which 
  are 
  usually 
  closely 
  an- 
  

   kylosed, 
  and 
  appear 
  continuous, 
  with 
  a 
  narrow, 
  flattened 
  area 
  on 
  

   either 
  side; 
  lower 
  half 
  of 
  the 
  delthyrium 
  open, 
  for 
  the 
  reception 
  of 
  

   the 
  beak 
  of 
  the 
  brachial 
  valve. 
  Teeth 
  prominent, 
  arising 
  from 
  the 
  

   bottom 
  of 
  the 
  valve 
  ; 
  above 
  the 
  hinge 
  line 
  they 
  curve 
  backward 
  and 
  

   toward 
  each 
  other, 
  thus 
  making 
  a 
  very 
  firm 
  articulation. 
  Muscular 
  

   area 
  well 
  defined. 
  Brachial 
  valve 
  with 
  median 
  fold, 
  and 
  minute 
  

   beak. 
  Hinge 
  plate 
  greatly 
  elevated, 
  with 
  a 
  small 
  chilidium 
  resting 
  

   against 
  it; 
  upper 
  face 
  of 
  plate 
  deeply 
  divided 
  by 
  median 
  longitudinal 
  

   groove, 
  and 
  more 
  faintly 
  by 
  transverse 
  groove. 
  Dental 
  sockets 
  

   small 
  and 
  deep, 
  crura 
  broad, 
  thin 
  and 
  comparatively 
  short. 
  Brachi- 
  

   dium 
  of 
  two 
  spiral 
  cones 
  set 
  base 
  to 
  base, 
  as 
  in 
  S 
  p 
  i 
  r 
  i 
  f 
  e 
  r 
  . 
  

  

  Trematospira 
  camura 
  Hall 
  (Fig. 
  

   122). 
  Atrypa 
  camura 
  Hall 
  (1852. 
  

   Pal. 
  N. 
  Y. 
  2:2ys, 
  pL 
  56) 
  

  

  Distinguishing 
  characters. 
  Small 
  ; 
  

   subrhomboidal 
  to 
  transversely 
  elon- 
  

   gate; 
  nearly 
  equally 
  convex 
  valves. 
  

   Small, 
  acute, 
  proiectinsf 
  and 
  slightlv 
  in- 
  

  

  ^ 
  ■> 
  «= 
  o 
  . 
  pjg 
  J22 
  Trematospira 
  camura 
  

  

  curved 
  beak 
  of 
  pedicle 
  valve, 
  showing 
  

  

  in 
  young 
  shells 
  the 
  ankylosed 
  deltidial 
  plates; 
  strong, 
  distant, 
  simple 
  

   subangular 
  plications, 
  one 
  or 
  two 
  fine 
  ones 
  in 
  the 
  center; 
  fine, 
  

   thread-like 
  concentric 
  striae 
  and 
  coarse 
  lamellae. 
  

  

  Found 
  in 
  the 
  Bryozoa 
  beds 
  of 
  the 
  Rochester 
  shale 
  at 
  Niagara, 
  

   rather 
  common. 
  Also 
  at 
  Lockport 
  and 
  elsewhere 
  (Hall). 
  

  

  Genus 
  whitfieldella 
  Hall 
  & 
  Clarke 
  

  

  [Ety. 
  : 
  proper 
  name] 
  

  

  (1893. 
  Pal. 
  N. 
  Y. 
  V. 
  8, 
  pt 
  2, 
  p. 
  58) 
  

  

  Shells 
  usually 
  of 
  small 
  size; 
  valves 
  subequally 
  convex, 
  ovate 
  or 
  

   elongate 
  in 
  outline; 
  beak 
  of 
  pedicle 
  valve 
  not 
  high 
  or 
  greatly 
  in- 
  

  

  ^ 
  

  

  